/**
 * WebDAV Handler Module
 * 
 * This module implements the WebDAV protocol (RFC 4918) endpoints for OxiCloud.
 * It provides a complete WebDAV server implementation that allows clients to
 * perform file operations over HTTP, including reading, writing, and manipulating
 * files and directories.
 * 
 * The WebDAV protocol extends HTTP to provide file system-like functionality, enabling:
 * - File/folder listing (PROPFIND)
 * - Creation of collections/directories (MKCOL)
 * - Retrieving and updating resources (GET, PUT)
 * - Moving and copying resources (MOVE, COPY)
 * - Resource locking for concurrency control (LOCK, UNLOCK)
 * 
 * This implementation leverages OxiCloud's existing file and folder services
 * through the application's port interfaces.
 */

use std::sync::Arc;
use axum::{
    Router, 
    routing::get,
    extract::{Path, State, Request, Extension},
    http::StatusCode,
    response::Response,
};
use http::{Method, header};

use crate::common::di::AppState;
use crate::interfaces::middleware::auth::CurrentUser;
use crate::application::ports::file_ports::{FileRetrievalUseCase, FileUploadUseCase};
use crate::application::ports::folder_ports::FolderUseCase;
use crate::common::errors::AppError;
use crate::application::adapters::webdav_adapter::WebDavAdapter;

/**
 * Creates and returns the WebDAV router with all required endpoints.
 * 
 * This function sets up all WebDAV method handlers following RFC 4918,
 * mapping HTTP methods to appropriate WebDAV operations.
 * 
 * @return Router configured with WebDAV endpoints
 */
pub fn webdav_routes() -> Router<Arc<AppState>> {
    Router::new()
        // Standard HTTP methods used in WebDAV
        .route("/webdav/*path", get(handle_get))
        .route("/webdav/*path", axum::routing::head(handle_head))
        .route("/webdav/*path", axum::routing::put(handle_put))
        .route("/webdav/*path", axum::routing::delete(handle_delete))
        
        // WebDAV-specific methods
        .route_with_tsr("/webdav/*path", axum::routing::on(
            Method::OPTIONS, handle_options,
            Method::PROPFIND, handle_propfind,
            Method::PROPPATCH, handle_proppatch,
            Method::MKCOL, handle_mkcol,
            Method::COPY, handle_copy,
            Method::MOVE, handle_move,
            Method::LOCK, handle_lock,
            Method::UNLOCK, handle_unlock,
        ))
}

/**
 * Handles OPTIONS requests to advertise WebDAV capabilities.
 * 
 * This handler responds with the DAV header indicating WebDAV compliance
 * level and the methods supported by this WebDAV server.
 * 
 * @param state The application state containing service dependencies
 * @param path The requested resource path
 * @return HTTP response with appropriate WebDAV headers
 */
async fn handle_options(
    State(_state): State<Arc<AppState>>,
    Path(_path): Path<String>,
) -> Response {
    Response::builder()
        .status(StatusCode::OK)
        .header(header::DAV, "1, 2") // Class 1 and 2 WebDAV support
        .header(header::ALLOW, "OPTIONS, GET, HEAD, PUT, DELETE, PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, LOCK, UNLOCK")
        .body(axum::body::Body::empty())
        .unwrap()
}

/**
 * Handles PROPFIND requests to retrieve resource properties.
 * 
 * This handler processes WebDAV PROPFIND requests, which are used to retrieve
 * properties for one or more resources. It supports different depths (0, 1, infinity)
 * and can return all properties or a specified subset based on the request.
 * 
 * @param state The application state containing service dependencies
 * @param user The authenticated user making the request
 * @param path The requested resource path
 * @param request The full HTTP request containing headers and body
 * @return XML response with requested properties
 */
async fn handle_propfind(
    State(state): State<Arc<AppState>>,
    Extension(user): Extension<CurrentUser>,
    Path(path): Path<String>,
    request: Request<axum::body::Body>,
) -> Result<Response, AppError> {
    // Extract depth header (0, 1, or infinity)
    let depth = request
        .headers()
        .get(header::from_str("Depth").unwrap())
        .and_then(|v| v.to_str().ok())
        .unwrap_or("infinity");
    
    // Read request body to determine which properties are requested
    let body_bytes = hyper::body::to_bytes(request.into_body()).await
        .map_err(|e| AppError::bad_request(format!("Failed to read request body: {}", e)))?;
    
    // Use the adapter to parse the PROPFIND request
    let prop_find_request = WebDavAdapter::parse_propfind(&body_bytes[..])
        .map_err(|e| AppError::bad_request(format!("Invalid PROPFIND request: {}", e)))?;
    
    // Determine if the path is a file or directory
    let is_file = if path.ends_with('/') {
        false
    } else {
        // Check if path exists as a file
        let file_service = state.file_service.as_ref()
            .ok_or_else(|| AppError::internal_error("File service not configured"))?;
        
        match file_service.file_retrieval_service.get_file_by_path(&path, &user.id).await {
            Ok(_) => true,
            Err(_) => false,
        }
    };
    
    if is_file {
        // Handle PROPFIND for a file
        let file_service = state.file_service.as_ref()
            .ok_or_else(|| AppError::internal_error("File service not configured"))?;
        
        let file = file_service.file_retrieval_service.get_file_by_path(&path, &user.id).await?;
        
        // Generate XML response
        let mut xml_buffer = Vec::new();
        WebDavAdapter::generate_propfind_response_for_file(
            &mut xml_buffer,
            &file,
            &prop_find_request,
            depth,
            &format!("/webdav/{}", path),
        ).map_err(|e| AppError::internal_error(format!("Failed to generate XML response: {}", e)))?;
        
        // Return response with appropriate headers
        Ok(Response::builder()
            .status(StatusCode::MULTI_STATUS)
            .header(header::CONTENT_TYPE, "application/xml; charset=utf-8")
            .body(axum::body::Body::from(xml_buffer))
            .unwrap())
    } else {
        // Handle PROPFIND for a directory
        let folder_service = state.folder_service.as_ref()
            .ok_or_else(|| AppError::internal_error("Folder service not configured"))?;
        
        let folder_path = if path.ends_with('/') { path.clone() } else { format!("{}/", path) };
        let folder = folder_service.get_folder_by_path(&folder_path, &user.id).await?;
        
        // Fetch children if depth > 0
        let (files, folders) = if depth == "0" {
            (Vec::new(), Vec::new())
        } else {
            let files = file_service.file_retrieval_service.get_files_in_folder(
                Some(&folder.id.to_string()),
                &user.id,
            ).await?;
            
            let folders = folder_service.get_subfolders(
                Some(&folder.id.to_string()),
                &user.id,
            ).await?;
            
            (files, folders)
        };
        
        // Generate XML response
        let mut xml_buffer = Vec::new();
        WebDavAdapter::generate_propfind_response(
            &mut xml_buffer,
            Some(&folder),
            &files,
            &folders,
            &prop_find_request,
            depth,
            &format!("/webdav/{}", folder_path),
        ).map_err(|e| AppError::internal_error(format!("Failed to generate XML response: {}", e)))?;
        
        // Return response with appropriate headers
        Ok(Response::builder()
            .status(StatusCode::MULTI_STATUS)
            .header(header::CONTENT_TYPE, "application/xml; charset=utf-8")
            .body(axum::body::Body::from(xml_buffer))
            .unwrap())
    }
}

/**
 * Handles GET requests to retrieve file contents.
 * 
 * This handler streams file contents to the client with appropriate
 * content type and other metadata headers.
 * 
 * @param state The application state containing service dependencies
 * @param user The authenticated user making the request
 * @param path The requested file path
 * @return Streaming response with file contents
 */
async fn handle_get(
    State(state): State<Arc<AppState>>,
    Extension(user): Extension<CurrentUser>,
    Path(path): Path<String>,
) -> Result<Response, AppError> {
    // Ensure this is a file request (not a directory)
    if path.ends_with('/') {
        return Err(AppError::bad_request("Cannot GET a directory"));
    }
    
    let file_service = state.file_service.as_ref()
        .ok_or_else(|| AppError::internal_error("File service not configured"))?;
    
    // Get file metadata
    let file = file_service.file_retrieval_service.get_file_by_path(&path, &user.id).await?;
    
    // Stream file content
    let stream = file_service.file_retrieval_service.get_file_stream(&file.id, &user.id).await?;
    
    // Return streamed response with appropriate headers
    Ok(Response::builder()
        .status(StatusCode::OK)
        .header(header::CONTENT_TYPE, file.mime_type)
        .header(header::CONTENT_LENGTH, file.size.to_string())
        .header(header::ETAG, format!("\"{}\"", file.id))
        .header(header::LAST_MODIFIED, file.updated_at.to_rfc2822())
        .body(axum::body::Body::from_stream(stream))
        .unwrap())
}

// Implement remaining WebDAV method handlers...

/**
 * Handles HEAD requests to retrieve file metadata without content.
 * Similar to GET but without returning the file body.
 */
async fn handle_head(
    State(state): State<Arc<AppState>>,
    Extension(user): Extension<CurrentUser>,
    Path(path): Path<String>,
) -> Result<Response, AppError> {
    // Implementation similar to handle_get but without body
    // ...
    todo!()
}

/**
 * Handles PUT requests to create or update files.
 * Streams the request body to create or replace a file.
 */
async fn handle_put(
    // ...
) -> Result<Response, AppError> {
    todo!()
}

/**
 * Handles PROPPATCH requests to update resource properties.
 * Processes property updates and removals.
 */
async fn handle_proppatch(
    // ...
) -> Result<Response, AppError> {
    todo!()
}

/**
 * Handles MKCOL requests to create directories.
 * Creates a new collection (directory) at the specified path.
 */
async fn handle_mkcol(
    // ...
) -> Result<Response, AppError> {
    todo!()
}

/**
 * Handles DELETE requests to remove resources.
 * Deletes the specified file or recursively deletes a directory.
 */
async fn handle_delete(
    // ...
) -> Result<Response, AppError> {
    todo!()
}

/**
 * Handles COPY requests to duplicate resources.
 * Copies a file or recursively copies a directory.
 */
async fn handle_copy(
    // ...
) -> Result<Response, AppError> {
    todo!()
}

/**
 * Handles MOVE requests to relocate resources.
 * Moves or renames a file or directory.
 */
async fn handle_move(
    // ...
) -> Result<Response, AppError> {
    todo!()
}

/**
 * Handles LOCK requests for concurrency control.
 * Locks a resource for exclusive access by a client.
 */
async fn handle_lock(
    // ...
) -> Result<Response, AppError> {
    todo!()
}

/**
 * Handles UNLOCK requests to release locks.
 * Releases a previously acquired lock on a resource.
 */
async fn handle_unlock(
    // ...
) -> Result<Response, AppError> {
    todo!()
}